Tremolo device



March 15 192 7 B. E. MILLS TREMOLO DEVICE Filed March 24, 1926 2SheetS-Shee`b l.

Mar h l c 5 1927 B. E. MILLS TREMOLO DEVICE Eve/m?.-

2 Sheets-Sheet 2 Qn f wmki Filed March 24 1926 Patented Mar. 15, 1927.

.- lTED TFJS BERTIE E. MILLS, GF OAK PARK, ILLN 01S, ASSIGNOB TO MLLSNOVELTY COMPANY, OF CI-IXCAGO, ILLINOS, A COREORATON OF ELLNOIS.

TREMOLO DEVICE.

Application lcd March 24, 1926.

This invention relates particularly to a tremolo device forstringed-instruments of the viol class in music machines, such as thoseemploying electrical actuating means.

The primary object is to provide an improved means for producing tremoloeffects in machines of the character mentioned.

The invention is illustrated in a preferred embodiment in theaccompanying drawings, in which- Fig. l represents a broken elevationalview of string-tensioning means and pulsatingmeans connected therewith;Fig. l, a fragmentary view of one of the tensioning-levers shown in Fig.1; Fig. 9., a broken plan view,

partly in section, of the improved pump device and pulsating-means; andFig. 3. a broken vertical section taken as indicated at line 3 of Fig.2.

The views may be regarded as somewhatdiagrammatic in their nature.

In the construction illustrated, A designates the neck-portion of aviolin, for eX- ample, which is equipped with strings 1 B,tensioning-means for said strings; C, pulsating-means associated withsaid tensioning-means and comprising individual pulsating-devices forvibrating each of the several tensioning-levers: D, pumping-meansactuated by a solenoid D and provided with a conduit D2 which serves allofthe pulsating-devices; D3, a circuit-controlling device associatedwith the pump D; E, a manuallyadjusted valve controlling the conduit D2;E', an electro-magnetically controlled valve also controlling theconduit D and F, an electro-magnetic device, controlling the valve E.

The normal tension of the strings l is applied through thetensioning-means B comprising, in the illustration given. a series ofindividual tension devices, each of which consists of a tension-leverconnected with the corresponding string, and a coil-spring ofadjust-able tension. There are four tensionlevers corresponding with thefour strings of aviolin. Two of the levers, designated 2 and 3, are seenin Fig. l. They have pivotally connected therewith links 2a and 3a. Thesprings 4 (one shown) are connected at one end by means of such linkswith the individual levers. At the other end the springs are connectedwith individual tension-adjusting devices 5 (one shown).

Each string l passes freely over a grooved Serial No. 96,983.

sector la of the corresponding lever and is adjustably secured to thelever by an adjusting device 1b. The adjustment of strings, levers andsprings is such that the strings are under normal tension with thelevers in horizontal position; and the springs preferably are at anangle of 45 with relation to the plane of the levers. It has been foundwith such relation of the parts, the levers may be vibrated suflicientlyto give the desired tremolo effect without substantially varying theeffective turning moments of the springs and levers.

The pulsating-means C comprises a cylinder 6 and ay piston a for eachtensioninglever. The piston-rods shown are designated 6b. It will benoted that in the case of the longer lever 3 the connecting rod ispivotally joined to the extremity of the lever at 7, while the link 32is pivotally joined to the lever at 8. In the case of the lever 2, boththe link 2a and the connecting-rod are v connected with the lever by apivot-pin 9.

It may be noted here that the pistons 6a need not lit closely within thecylinders 6. The cylinders are served with compressed air, orair-pulsations, through individual conduits 10 extending through a blockor valve-casing, l()a fitted with controlling valves 10b. The ports 10are served from a common conduit 11, which is, in effect, a continuationof the conduit D2 leading from the pump D. It is desirable that thetensioning-levers be vibrated rapidly to produce the desired tremoloeffect, but the amplitude of movement of each lever preferably is suitedto the corresponding string. The low string, for example. requiresgreater tension-variation than the high string. The amplitude ofmovement and (if desired) the rate of vibration may be varied toaccomplish the desired result.

The valves 10b may be used to regulate the admission, or feed, ofair-pulsations from the common conduit l1 to the severalpulsating-devices. Thus, notwithstanding a single pumping mechanismserves all the pulsating devices.7 each pulsating device may beregulated to impart the vibrations suited to its particular lever andstring.

Again, the valve E may be set to approximately regulate the feed to theconduit 11, and the valve E may be controlled by a switch located at anydesired point, as for example on a console iitted with a key manlll)ual. Thus, the valve E may serveas an auxiliary valve, convenientlycontrolled from any point, to vary the feed of air through the conduitD2 to the passage 11, at will.

The Vpump D preferably is actuated by an electro-magnetic device. Thepreferred construction and arrangement is illustrated 4as comprising acylinder 12; a plunge-r 13 i'itted with a piston 13a; the solenoid Dencircling or wrapped on the cylinder 12; and

a coil-spring le which serves to retract the piston after it has beenactuated .by the solenoid D.

The walls of the cylinder12 may be of non-magnetic material, plunger 13and piston 13a serve as a magnetic core, or plunger. The parts should besuitably designed to enable the solenoid to actuate the piston duringits working stroke, i. e. in moving to the lett-hand end of the cylinderas shown in 3. During this working stroke air is forced in regulatedquantity through the outlet port 15 (Fig. 2), past the valves E and Einto the conduit D2 and thence to the pulsating-means C. During theworking-stroke of the piston, the tension of spring 14 is increased andlater the spring retracts the piston.

The left-hand end of the plunger 13, designated 13b, may be of brass orother nonmagnetic material.

The plunger 13 has aprojecting end-portion fitted with a flange 13cwhich serves to actuate the circuit-controller D3 which controls thecircuit 16 of the solenoid D. The circuit 16 may be equipped, also, witha switch 16a which may be located at any convenient point.

In the example given, the solenoid D actuates the pump-piston in onedirection and places the spring 14 under sutllcient tension to retractthe'piston after the solenoid is de-energized. With such arrangement andoperation, the piston, as it approaches the end of its working stroke,throws the switch D3 to circuit-breaking position, and when the pistonis retracted the switch is again thrown to the circuit-closing position.

As shown, the switch D3 is mounted on a pivot 17 and is equipped withactuating arms 18 and 19 adapted to be engaged by the flange 13C. Theswitch has a contact-arm 2O which co-acts Ywith a contact pointl 21 withwhich the circuit 16 is provided.

The valve E is normally open, or partially open. lt has an actuating arm22 connected with the movable core 23 of the solenoid F. A compressionspring 24 tends to hold the core 23 in the normally displaced positionshown in Fig. 2. rlhe solenoid is provided with a circuit 25 equippedwith a switch 25L which may be located at any suitable point. Thus, theswitch may be at a point remote from the solenoid and the valve if fdesired. The

E may be controlled therefrom. By closing the circuit, the solenoid willbe energized and caused to draw in the core 26, thus restricting lorclosing the passage at the valve E. Y

From the description given, it will be understood that the inventionprovides for giving an improved tremolo etiect in a very simple mannerand bymeans of very simple and readily controlled mechanism.

Obviously, the solenoid D can be inade'to ctuater the pui'np-piston inone or both directions, as desired, the arrangement described bei aprefered arrangement. ln fact, any suitable electro-magnetic device mayhe employed for actuating the pumppiston, the latter g, l inaticallyshiit tlie circuit-changer, as Y required.

ln practice, it is preferred to give the piston 6L a fairly close litwithin the cylinders 6, and to so operate the pump device that it willpulsate air hack and forth through the conduit .D2 as the piston of thepump device reciprocates. Thus, when the piston moves to the le t, asviewed inllig. 6, air will be forced through the conduit D2 into thepassage 11 and serve to elevate 'the pistons and w en the air recedesfrom the cylinders of the pulin. '-device C, allowing the pistons 6L toescend. The return movement of the pison 13C ot the pump device D may bereguatet. by providing the end of the ,cylinder with'an i a valve 27 forregulating the size of the discharge passage. Thus-therate of thepulsations may be regulated by regulating the movement of the piston13a.

rl`he foregoing detailed description: has been given for clearness ofunderstanding only, andl no unnecessary limitations should be understoodtherefrom, but the'appended claims'should be construed as broadly 'aspermissible, in view of the prior art.

What l regard as new, and desire to secure CD by Letters Patent, is: Y

1. In combination with a string-tensioning device of a stringedinstrument of the viol class, a tremolo-device comprising apulsating-device connected with said tensioning-device, a pump providedwith a conduit serving said pulsating-device, a solenoid serving toactuate said pump, and an electric circuit for said solenoid controlledby said pump.

2. In combination with astring-tensioning .device ofa stringedinstrument of the Vviol class, treinolo-device comprising apulsating-device connected with said tensioning-device, a pumpcomprising a cylinder and a reciprocating piston, yielding means servingto -actuate said piston in one direction, a solenoid serving to act-natesaid piston in the other direction, an electric circuit serving in turn,to autodischarge passage 26 litted with pump-piston is retracted,

for said solenoid, circuit-controlling means actuated by said piston anda conduit leading from said pump anc serving said pulsating-device.

3. In combination with a pulsating-device for actuating astring-tensioning device, pumping means comprising a cylinder equippedwith a solenoid, a pump-piston Within said cylinder actuated by saidsolenoid, a conduit leading from said cylinder and serving saidpulsating-device, an electric circuit for said solenoid, andcircuitcontrolling n'ieans actuated by said piston.

4. In combination with a pulsating-device for actuating astring-tensioning device, pumping means comprising a cylinder equippedWith a solenoid, a pump-piston Within said cylinder actuated by saidsolenoid, a conduit leading from said cylinder and serving saidpulsating-device, an electric circuit :tor said solenoid, and anoscillating circuit-maker and breaker actuated in both direct-ions bysaid piston.

5. In combination with a string-tensioning lever, a pulsating-device, apump serving said pulsating-device and having a reciprocating piston,and an electro-magnetic device serving to actuate said piston and havinga circuit controlled by the movements of said piston.

6. In combination with string-tensioning nieans and co-actingpulsating-means, a pump having a conduit serving said pulsating-means, avalve controlling said conduit, and an electro-magnetic device foractuating said valve.

7. In combination With string-tensioning means and co-actingpulsating-means, a pump having a con-duit serving said pulsating-meansand having a reciprocating piston, a valve controlling` said conduit,and electro-magnetic devices tor actuating said piston and said valve.

8. In combination with string-tensioning means and co-acting pulsatingmeans, a punip having a conduit serving said pulsating-means and havinga reciprocating piston, a valve controlling said conduit, anelectro-magnetic device serving to actuate .said piston and controlledby said piston, and an independent electro-magnetic device controllingsaid valve.

9. In combination with string-tensioning levers and separatepulsating-devices connected therewith, valve-controlled conduits leadingto said pulsating-devices, and a pump .serving all of said conduits.

10. In combination with .string-tensioning levers and separatepulsating-devices connected therewith, valve-controlled conduits leadingto said pulsating-devices, a pump having a. conduit serving all saidlirstnamed conduits, and a valve controlling said second-mentionedconduit.

11. In combination with string-tensioning levers and separatepulsating-devices connected therewith, valve-controlled conduits leadingto said pulsating-devices, a pump having a conduit serving all saidirst-nanied conduits, a manually adjusted valve gua-rding saidsecond-mentioned conduit, and also an electro-magnetically controlledvalve controlling said second-mentioned conduit.

BER'IIE E. MILLS.

